#include<iostream>
#include<vector>
using namespace std;

int missingNumber(vector<int>& nums) {
    int left = 0, right = nums.size() - 1;
    while (left < right) {
        int mid = left + (right - left) / 2;
        if (nums[mid] == mid) left = mid + 1;
        else right = mid;
    }
    return left;
}


int main()
{
    vector<int> nums = { 3,0,1 };
    missingNumber(nums);
    return 0;
}